| dc.description.abstract | Quantum mechanics was invented in an era of intense and seminal scientific research
between 1900 and 1928 (and in many regards continues to be developed and
expanded) because neither the properties of atoms and electrons, nor the spectrum of
radiation from heat sources could be explained by the classical theories of mechanics,
electrodynamics and thermodynamics. It was a major intellectual achievement
and a breakthrough of curiosity driven fundamental research which formed quantum
theory into one of the pillars of our present understanding of the fundamental laws
of nature. The properties and behavior of every elementary particle is governed by
the laws of quantum theory. However, the rule of quantum mechanics is not limited
to atomic and subatomic scales, but also affects macroscopic systems in a direct
and profound manner. The electric and thermal conductivity properties of materials
are determined by quantum effects, and the electromagnetic spectrum emitted by a
star is primarily determined by the quantum properties of photons. It is therefore
not surprising that quantum mechanics permeates all areas of research in advanced
modern physics and materials science, and training in quantum mechanics plays a
prominent role in the curriculum of every major physics or chemistry department.
The ubiquity of quantum effects in materials implies that quantum mechanics
also evolved into a major tool for advanced technological research. The construction
of the first nuclear reactor in Chicago in 1942 and the development of
nuclear technology could not have happened without a proper understanding of
the quantum properties of particles and nuclei. However, the real breakthrough
for a wide recognition of the relevance of quantum effects in technology occurred
with the invention of the transistor in 1948 and the ensuing rapid development
of semiconductor electronics. This proved once and for all the importance of
quantum mechanics for the applied sciences and engineering, only 22 years after
publication of the Schrödinger equation! Electronic devices like transistors rely
heavily on the quantum mechanical emergence of energy bands in materials, which
can be considered as a consequence of combination of many atomic orbitals or
as a consequence of delocalized electron states probing a lattice structure. Today
the rapid developments of spintronics, photonics and nanotechnology provide
continuing testimony to the technological relevance of quantum mechanics. | en_US |
